The present invention relates to a method and layout for positioning robots in an automobile painting line. More specifically, it relates to a method and layout for positioning robots that makes it possible to halve the total length of an automobile line, especially in a sealing line and a painting line for applying a rust-prevention material on the automobile body.
In a conventional automobile manufacturing line, a number of robots such as spot-welding robots, sealing robots, and painting robots are disposed in series, divided in stages dependent on the work to be done thereby. Dividing the robots into work stages and disposing them in series in this manner has the advantage of making it unnecessary to consider the effects that the operation of each robot will have on the other stages, and it also facilitates tasks such as work management, stage management, and robot control.
The positioning of robots within a painting line for applying a rust-prevention material and chip guard to the hidden reverse under-surface of the floor of an automobile body B together with that of a sealing line for water-proofing the joints of the automobile body B, which is provided after an electrodeposition painting line constructed according to the above design concept, is shown in FIGS. 7 to 15. In these figures, P denotes a painting robot, S denotes a sealing robot, F denotes a hood-operating robot, and G denotes a trunk-operating robot (a robot for opening and closing the luggage compartment of an automobile).
However, if robots are disposed in the above layout to form a manufacturing line, the length of this line is inevitably long, resulting in the following problems:
1. A large area on site is necessary for the factory building in which the robots are disposed. PA0 2. The conveyor facilities will also become longer, making it necessary to increase the conveyor length and the numbers of hangers and dollies correspondingly. PA0 3. The installation and running costs for air conditioning (including temperature, humidity, and cleanliness control) also increase. PA0 4. It is difficult to recycle non-attached paint materials (which are environmental pollutants) and thus a large quantity of sludge processing water is used. PA0 5. The total time required of tasks (work tasks) for each automobile increases. PA0 6. Since most of the problems with automobile manufacturing lines are related to the conveyor facilities, lengthening the manufacturing line will increase the likelihood that the manufacturing line will be halted by problems in the conveyor facilities. PA0 7. When a manufacturing line has been halted, the quality of paint layers in the painting line deteriorates. Lengthening the manufacturing line increases the drawbacks that such deterioration will occur in the paint quality of large number of automobiles.
It should be noted that a previous proposal related to the positioning of robots for an automobile manufacturing line was disclosed in Japanese Laid-Open Patent Publication (KOKAI) No. 6-654. The objective thereof is to implement uniform additional welding for an entire automobile body at a welding station at the initial end of an additional welding (Mashiuchi) line, to prevent the occurrence of welding distortion at the additional welding stage of this automobile manufacturing line. Side frames 110, each having an upper level 111 and a lower level 112, are provided on each side of a welding station 100, as shown in FIG. 16. The additional welding is performed on joint portions between the floor and side panels of an automobile body B by robots 120 which are mounted on the lower levels 112 and are capable of moving towards and away from the sides of the automobile body B, while the additional welding is performed on joint portions between the roof and side panels of the automobile body B by robots 120 which are mounted on the upper levels 111 and are capable of moving towards and away from the sides of the automobile body B. In addition, two suspended robots 140 are mounted fore and aft from a ceiling framework 130 of the welding station 100 in such a manner that they are free to travel horizontally and are capable of moving vertically. These robots 140 are intended to perform the additional welding on joint portions for other structural members of the automobile body B such as the dashboard.
However, a downflow circulatory system is established in such a painting line to prevent flying dust and dirt from attaching to the automobile body B. When a bulky robot body is moved vertically above the automobile body B, a large disruption (turbulence) is caused in the downflow circulation and the resultant dust and dirt is entrained in the airflow and can attach to the layers of paint, leading to deterioration of the paint quality. Similarly, when such a bulky robot body travels toward the automobile body B when in the vicinity of the automobile, the movement of the robot causes a large disruption in the downflow circulation, and the resultant dust and dirt is entrained in the circulation as described above and can attach to the layers of paint, leading to deterioration of the paint quality. For that reason, the robot positioning layout proposed by the above laid-open patent publication cannot be applied as is to a painting or sealing line.